Method and apparatus for cutting lumber to random or specified clear lengths

ABSTRACT

A piece of lumber is fed flat to the infeed end of a marking station, tilted on edge and driven endwise into the marking station where defects in the piece are detected and marked with a retroreflective material. The marked piece moves to a defectcutting station where it is driven endwise past a pair of defectcutting saws until a marked defect is sensed between the saws to stop movement of the piece and actuate the saws to remove the defective section. The clear piece downstream of the saws is measured and, if longer than a minimum length range, diverted to a cut-to-length saw station. If within the minimum length range, it is diverted to a &#39;&#39;&#39;&#39;core block&#39;&#39;&#39;&#39; sort. If shorter than the minimum range, it is diverted to junk. The piece upstream of the saws is measured and diverted in the same manner as the downstream piece except that upstream pieces longer than the minimum length range resume travel past the defect saws. Longlength sensors at the defect station determine if a piece contains any one of several specified defect-free long lengths and if so, set a stop downstream of the defect saws corresponding to the longest specified clear length sensed and then actuate only one of the defect saws to cut the piece to such length when the piece reaches the set stop. Such piece is then diverted directly to a sorting station. Random length clear pieces transferred to the cut-to-length station are pressed against a series of depressible stop-sensors determining various specified lengths, driven endwise over the stop-sensors past a length saw until one of the stop-sensors is released, then driven in reverse against the released stop. The length saw then strokes to cut the piece to specified length, after which the piece is sorted according to length as determined by the released stop-sensor.

United States Patent [191 Miles METHOD AND APPARATUS FOR CUTTING LUMBERTO RANDOM 0R SPECIFIED CLEAR LENGTI'IS [75] Inventor: Thomas R. Miles,Portland, Oreg.

[73] Assignee: Edward Hines Lumber Co., Hines,

Oreg.

[22] Filed: Dec. 30, 1971 [21] Appl. No.: 214,011

[52] US. Cl l44/3'N, 144/312, 83/71, 83/289, 83/365, 83/371, 83/522 [51]Int. Cl B27b 27/00 [58] Field of Search 144/312, 3 R, 3 N; 83/371,83/71, 365, 289, 468, 278, 522, 102, 105, 106, 209, 211, 212

Primary Examiner-Donald R. Schran Attorney, Agent, or Firm-Klarquist,Sparkman, Campbell, Leigh, Hall & Whinston' 571 ABSTRACT A piece oflumber is fed fiat to the infeed end of a marking station, tilted onedge and driven endwise into the marking station where defects in thepiece are The marked piece moves to a defect-cutting station where it isdriven endwise past'a pair of defect-cutting saws until a marked defectis sensed between the saws to stop movement of the piece and actuate thesaws to remove the defective section. The clear piece downstream of thesaws is measured and, if longer than a minimum length range, diverted toa cut-to-length saw station. If within the minimum length range, it isdiverted to a core block" sort. 1f shorter than the minimum range, it isdiverted to junk. The piece upstream of the saws is measured anddiverted in the same; manner as the downstream piece except thatupstream pieces longer than the minimum length range resume travel pastthe defect saws. Long-length sensors at the defect station determine ifa piece contains any one of several specified defect-free long lengthsand if so, set a stop downstream of the defect saws corresponding to thelongest specified clear length sensed and then actuate only one of thedefect saws to cut the piece to such length when the piece reachestheset stop. Such piece is then diverted directly to a sorting station.Random length clear pieces transferred .to the cut-tolength station arepressed against a series of depressible stop-sensors determining variousspecified lengths, driven endwise over the stop-sensors past a lengthsaw until one of the stop-sensors is released, then driven in reverseagainst the. released stop. The length saw then strokes to cut the pieceto specified length, after which the piece is sorted according to lengthas determined by the released stop-sensor.

29 Claims, 15 Drawing Figures PATENIE nuv 1 91974 WEE? 10F F THOMAS R.MILES INVENTOR LBUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS El owPATENTEL, 2 91914 $548,646 MEET 2 OF 7 THOMA5 R. MILES INVENTORBUCKHORN, BLORE, KLARQUIST & SPARKMAN ATTORNEYS PATENTE rm 1 9 I974 *MH3 UP 7 was R. MILES INVENTOR BUCKHORN, BLORE, KLARQUIST & SPARKMANATTORNEYS PATENTE raw 1 9 I974 Q 'mmm a MHLES 'INVENTOR BY E BUCKHORN,BLORE, KLARQUIST & SPARKMAN ATTORNEYS BUCKHORN, BLORE, KLARQUIST &SPARKMAN ATTORNEYS Pmmwwvwm 489L645 INPUT ONE SHO GATE "2 GATE "3 378377 CTL. FLlP-FLOP/ TIM ONE SHOT (H'L) SAW STROKE 234a L L L EXTEND 40(RETRA'CT OPEN CTL LOSE JUN K GATE 36 9 OPE CLOSE CTL. CORE 402/ BLOCKGATE THOMAS R. MILES INVENTOR BUCKHORN, BLORE, KLARQUIST & SPARKMANATTORNEYS 7 METHOD AND APPARATUS FOR CUTTING LUMBER TO RANDOM ORSPECIFIED CLEAR LENGTI-IS BACKGROUND OF THE INVENTION I. Field of theInvention The present invention relates to the cutting and sorting oflumber to random or specified clear lengths.

2. Description of the Prior Art Heretofore the removal of defects fromlumber and the cutting of the resulting clear pieces to one of severalspecified clearlengths with a minimum of waste has been largely amanual, trial-and-error operation. For example, in one typical priorsystem, each of ten saws manned by twenty people is equipped with a setof some twenty manually operated stops spaced at varying distances fromthe saw to'determine various specified lengths. Each sawyer takes alength of lumber, usually 16 ft. long, visually estimates the longestspecified length that can be cut between any two defects, places thelumber against the estimated swing stop and activates the cut-off saw.Approximately 40 percent of the time his estimate is not correct and hemust move the length of lumber to another swing stop, either shorter orlonger and then reposition the lumber to cut out the defective area.Thus each cut-tospecified-length piece requires one or more decisionsand positioning functions. Likewise each defect requires a positioningdecision and a subsequent cut. In addition the length of lumber isfrequently turned over to inspect the location of .defects on thereverse side.

Thus .as presently practised, the upgrading of low-gradedefect-containing lumber by cutting it to specified clear lengths is acostly, time-consuming operation, particularly with the high labor costsinvolved.

SUMMARY OF THE INVENTION The present invention provides a method andapparatus for removing defects from lumber and cutting the lumber torandom or specified clear lengths with a minimum of labor and at a highrate of production exceeding that possible with the aforementioned priormethod. The invention eliminates the human guesswork and trial-and-errorestimation of the longest specified clear length in a given piece oflumber involved with the prior method. The invention also eliminates themanual positioning and repositioning against stops.

A basic feature of the invention is the separation of the defectandlength-cutting operation into two sepa-. rate steps, including adefect-cutting step carried out at a first cutting station and acut-to-length step carried out at a subsequent cutting station.

A further basic feature of the invention is the use of each individualpiece of lumber to carry its own information necessary to triggervarious machine operations in proper sequence, thereby eliminating theneed for costly computer or memory systems to operate the apparatus.

Another feature of the present invention is a built-in sorting systemwhich sorts pieces according to length from length sensings made at thedefectand lengthcutting apparatus.

According to another feature of the invention, various specified clearlengths in a board are sensed automatically and these sensings used tooperate various elements of the apparatus as required to position theboard for cutting, to cut the board to a'specified length and to sortpieces according to length.

A more specific feature of the invention is the marking of defects in aboard with a retroreflective material which can be sensed to initiatemachine functions which either remove the defect from the board or cutthe board to a specified long clear length.

In another specific aspect of the invention, boards containing at leastone of several specified'long, clear lengths can be detected, positionedand cut automatically to the longest possible one of the specifiedlengths as the defect-cutting station and then diverted to acorresponding sorting station without passing through the cut-tolengthstation.

A prototype apparatus of the invention is designed to process l5,000board feet per day using from one to three persons, thereby giving aproduction rate per person of from 5,000 to 15,000 board feet. Thisshould be compared to the 1,500 board feet per person capable of beingproduced using the typical prior system previously described.

BRIEF DESCRIPTION OF DRAWINGS The foregoing and other objects, featuresand advantages of the present invention will become more apparent fromthe following detailed description which proceeds with reference to theaccompanying drawings, wherein:

FIG. 1 is a plan view of an overall system in accordance with theinvention;

FIG. 2 is a vertical sectional view on an enlarged scale takenapproximately along the line 2-2 of FIG. 1 showing the infeed endportion of the apparatus of FIG. 1;

FIG. 3 is a vertical section taken approximately along the line 33 ofFIG. 1 showing the details of the marking station portion of theapparatus;

FIG. 4 is a view taken along the line 4-4 of FIG. 3 showing an infeedportion of the marking station in plan;

FIG. 5 is a plan view of the sorting section of the apparatus of FIG. 1;

FIG. 5A is a continuation of FIG. 5 showing a plan view of an outfeedportion of the defect-cutting station;

FIG. 6 is a view taken approximately along the line 6--6 of FIG. 5showing the sawing and sorting sections of the apparatus in elevation;

FIG. 7 is a plan view of the cut-to-length station as viewed along theline' 7-7 of FIG. 6 rotated to a horizontal plane and with otherportions of the apparatus removed for clarity;

FIG. 8 is a partial sectional view taken along the lin 88 of FIG. 7 onan enlarged scale;

FIG. 9 is a sectional view taken along 'the line 9-9 of FIG. 7 on anenlarged scale;

FIG. 10 is a view taken along the line 10-10 of FIG. S-A showing one ofthe pop-out stops;

FIG. 11 is a view taken along the line ll-1I of FIG. 9 showing one ofthe stop-sensors;

FIG. 12 is a circuit diagram of the electrical sensing and controlsystem of the apparatus;

FIG. 13 is a circuit diagram of the pneumatic-fluidic sensing andcontrol system of the apparatus; and

FIG. 14 is a diagram of a manual control stick portion of the controlsystem.

DETAILED DESCRIPTION General Assembly With reference to the drawings,FIG. 1 shows the overall apparatus, including an infeed section 10, amarking station 12 just downstream from the infeed section where defectsare marked, and an operators station 14 alongside the marking station. Atransfer section 16 transfers marked lumber from the marking station 12to a cutting and sorting section 18. At the cutting and sorting section,marked defects are first detected and cut from pieces at adefect-cutting station 20 after which the resulting random-length clearpieces are dropped to a cut-to-length station 22 and then to a sortingsection 24 where the pieces are sorted to length.

Infeed Section Referring to FIGS. 1 and 2, pieces from a stack of lumber26 on a scissors lift 27 at the head of the infeed section are fed ontoa declining skate wheel section 28 leading to a zero trim table 30.Pieces roll down the skate wheels 28 onto a series of driven endingrolls 32 which drive the pieces endwise against an ending bumper 34. Lugchains 36 push one piece at a time from the ending rolls through a zerotrim saw 38 and onto a declining skidway comprising a series of skidrails 40. Each piece P slides down the rails in a flat condition to astop 42 at the bottom of the skidway. As each piece arrives at the stop,it has its right-hand end as viewed in FIG. 1 referenced in the sameposition as every other piece with respect to the infeed end of themarking station 12 regardless of the length of the piece because of thezero-referencing action of the zero trim table.

At the lower end of the skidway, means are provided for turning eachboard on edge and for flipping it completely over. Such means includes aflipper arm assembly comprising a series of flipper arms 44 mounted atspaced intervals along a common shaft 46. As clearly shown in FIG. 2,the flipper arms in their inactive positions lie below apiece of lumberP at the bottom of the skid rails. The flipper arm assembly is actuatedby a tandem pair of air cylinders 47, 48 pivoted to the frame of themachine at 49 and pivoted at 50 to a crank arm 51 of shaft 46. Uponextension of cylinder 47, arm 44 pivots to an inclined position 44a tolift a piece P on edge as shown. Upon extension of both cylinders 47,48, arm 44 is pivoted to a near vertical position 44b to lift a piece Pcompletely over to its opposite face. The flipper assembly is controlledfrom the operators station 14. There the operator, positioned in a seat53 on a platform 54, overlooks the flipper assembly and can flip a givenboard so that its most defective face will be tilted toward the operatoras it passes through the marking station 12.

If desired, the zero trim table can be eliminated and additional skatewheels or other means provided for feeding pieces of lumber manually oneat a time onto the skid rails 40 for manipulation by the flipper arms.

Lumber from stack 26 can be fed automatically to the skate wheels usingautomatic lumber feeder devices common in the industry. Alternatively, asecond person can be stationed at the stack on an extension 55 of theoperators platform and can manually feed one piece at a time from thestack 26 to the skate wheels.

Marking Station When a piece of lumber arrives at the bottom of the skidrails and is tilted on edge at approximately at angle to the horizontalby the flippers as shown in FIG. 3, its righthand end as viewed in FIGS.1 and 4 is supported by a wear plate 58 and the driven roll 60 of a pairof nip rolls at the infeed end of the marking station. The infeed niprolls also include an idler roll 61 movable toward and away from thedriven roll by an air cylinder 62. Nip roll 60 is driven by a reversibleorbit motor 64. Idler roll 61 is carried on an arm 65 pivoted at 66 to asupport 67. Wear plate 58 is downturned at its opposite ends as shown atinfeed end 68 to prevent boards from hanging up on the plate. The wearplate forms part of an angle member 69 and also includes a fence portion70 providing support for a back portion of a piece of lumber travelingalong the wear plate.

The wear plate defines a linear path of travel for a piece of lumber Pdriven endwise through the marking station by the infeed nip rolls. Thespeed and direction of endwise travel of a piece through the markingstation is controlled from the operators station by controlling thespeed and direction of rotation of motor 64.

A marking means shown most clearly in FIG. 3 is provided at the markingstation along the path of travel of a piece. The marking means includesa spray nozzle 72 directed toward the face of any board passing throughthe marking station. The nozzle is supplied with a fastdryingretroreflective liquid from a reservoir (not shown) which is sprayedunder control of the operator onto defects, such as knots, detected in aboard as it travels on edge through the marking station. Defects markedin this manner are detected later by photosensors which actuate sawsthat remove such defects. A defect can readily be aligned with themarking nozzle 72, which is preferably directly in front of the operatoras shown in FIG. 1, by reason of the reversible and variable speed driveprovided for the board.

The marking station also includes an outfeed means comprising a pair ofoutfeed nip rolls 74, 75 similar in arrangement and operation to theinfeed nip rolls 60, 61.

The opening and closing of both the infeed and the outfeed nip rolls arecontrolled automatically by photoelectric sensors shown schematically inFIG. 1 including an infeed sensor PO] and an outfeed sensor PC-2. Theinfeed sensor detects the presence of a board in position at the infeedend of the marking station and in response to such sensing closes thenormally open infeed nip rolls, driving the lumber into the markingstation. When the leading end of the lumber passes outfeed sensor PC-2,the outfeed nip rolls close enabling the lumber to be driven out of themarking station and onto the aligned end of the transfer section 16.

When a board moving through the marking station clears the infeed rolls60, 61, sensor PC-l causes such nip rolls to reopen to await delivery ofthe next board. Similarly, when the trailing end of the same boardclears the outfeed nip roll sensor PC-2, the outfeed nip rolls reopen toawait the next piece.

Transfer Section Transfer section 16 includes a series of screw rollsmounted on a frame table 82. The rolls are rotated by a chain drive 84in a direction so that lumber fed to the ends of the rolls in alignmentwith the marking station will be conveyed both downstream and sidewaysto the opposite ends of the rolls and up against a fence 86. The fenceserves to align each board endwise with the infeed end of thedefect-cutting station. An angled bumper plate 88 limits the downstreammovement of a board on the transfer table. Such plate also guides theleading end of each board toward a gate 94 and a pair of normally opennip rolls 90 at the infeed end of the defect-cutting station, as shownmost clearly in FIG. 5. Nip rolls 90 are similar to the nip rollspreviously described and include an air cylinder-actuated upper idlernip roll and an orbital motor driven lower nip roll, the air cylinderbeing shown at 91 and the orbit motor at 92.

Gate 94 is bounded on one side by a short fence section 96 and on theopposite side by a gate idler wheel 98 on bumper 88. The lower portionof the gate is defined partially by another idler wheel 99. Gate idler98is pivoted at 100 to a slide plate 102 and spring-biased toward the gateopening to prevent boards from moving through the opening until they arepositively driven by nip rolls 90. Slide plate 102 is slidablyadjustable along the upper surface of bumper 88 to adjust the size ofthe gate opening to accomodate various board widths.

Referring to FIG. 5, each screw roll 80 has two annular ribs 80a at itsinfeed end. These ribs prevent sidewise movement of the leading end of aboard as it is fed. onto the screwrolls by the outfeed nip rolls at themarking station until the entire board clears the outfeed nip rolls.When this happens, the edge-tilted board falls flat on the screw rollsenabling the helical ribs to begin their sideways conveying movement ofthe board toward fence 86.

A photoelectric sensor PC-3 at the infeed end of the transfer tablesenses the presence of a board on the table. This sensor illuminates ared warning light on a control panel at the operators station if thesensor remains activated too long, indicating a full table.

Another sensor PC-6 near gate 94 senses the presence of a board at thegate and between nip rolls 90 to close such rolls, enabling the infeedof a board into the defect station.

Defect-Cutting Station The details of the defect-cutting station areshown most clearly in FIGS. 5, S-A and 6. The relative levels of thedefect-cutting station, screw roll transfer section longitudinal andvertically stacked rectangular tube members 109, 110 supporting theother components of the defect-cutting station. All of theselongitudinal frame members extend between and are supported by crossframe members 112, 114.

A pair of parallel, longitudinally extending fence assemblies, one fixedand one laterally movable, define a linear, horizontal path of travelfor lumber fed endwise into and through the defect-cutting station. Thefixed fence assembly includes a short fixed fence 116 and a longer fixedfence 118, both defining continuations of the fence 86 of the transfersection and the short fence 96 of the gate leading into the defectstation. The movable fence assembly includes a short movable fence 120in opposition to the short fixed fence and a long movable fence 122opposite the long fixed fence 118.

The short movable and fixed fence sections are sus' pended beneath fencesupports 124, 125. The long fixed and movable fence sections aresupported from similar fence supports 126, 127 and 128. All of thesefence supports are longitudinally slotted as shown at 129 on support 127to receive suitable fasteners and to serve as slideways for the movablefence sections. The fence supports in turn are fixed to the tubularlongitudinal frame members 109, 110. Aircylinders 132 fixed to theunderside of fence supports 124, 125, 126 and 128 are connected also themovable fence sections for moving such sections in unison toward andaway from the fixed fence sections.

As shown best in FIG. 6 with respect to short fixed fence 116 and shortmovable fence 120, all fence sections carry bottom plates 134, 136 whichhave lip portions extending inwardly beyond the fence members themselvesto form a drop gate which either supports a board within the defectstation or drops a board from it, depending on the position of themovable fences. The plate 136 on the fixed gate sections is downtumed atits outer end so as to guide a board downwardly along an inclinedslideway when the movable fence is retracted by cylinder 132 to releasethe board.

The defect-cutting means includes a pair of defectcutting circular saws138, 139 positioned as shown in FIG. 5 in a gap between the short andlong fence sections. Saw 139 is mounted on a fixed base 140. However,saw 138 is mounted on an adjustable base 141 which enables the spacingbetween the pair of saws to be adjusted within the range of a fewinches, with such range, for example, normally being approximately fourto six inches. Except for the adjustable nature of the base of themovable saw, the mounting and actuation of the two saws is identical andso will be described only for the movable saw.

Saw 138 is fixed to a driven shaft 142 rotatably mounted on a yoke arm144. The yoke arm is pivoted to base 141 at 145. The yoke arm carries apulley wheel 146. A drive belt 148 interconnects the yoke arm pulley anda drive pulley 150 connected to the drive shaft of an electric motor 152for driving the saw. The motor is mounted on a base plate 153 which ispivoted at 154 to the main base 141.

The saw-actuating means includes a toggle mechanism 156 pivoted at oneend to an overhead frame member 157, at the other end to the yoke arm144 and in the center to an air cylinder 158 which in turn is connectedto an upright frame member 159. Thus in the normal inactive, retractedposition of the saw, air cylinder 158 is retracted to position the lowercutting edge of the saw above the level of a board P supported betweenthe fixed and movable fences. However, upon extension of the aircylinder, the toggle mechanism forces the yoke arm 144 downwardly andthen upwardly, thereby moving saw 138 through its cutting stroke tosever a board extending through the saws cutting plane. Normally boththe defect-cutting saws are actuated simultaneously to cut a shortdefective section from a board. The severed section then drops throughthe gap between fences to a junk" collection point. However, for areason to be developed later,

each saw is also capable of operating independently of the other.

The means for driving pieces through the defect station comprises a pairof relatively fixed driver rolls 162 and an opposing pair of relativelymovable idler rolls 164 mounted on opposite sides of the pair of defectsaws just inwardly toward the saws from adjacent ends of the fixed andmovable fence sections. Idler rolls 164 are carried by the movable fencesections so as to move with them. Driver rolls 162 are carried by thefixed fence sections. They are spring-loaded to extend a short distancebeyond the lumber-engaging edge of these fence sections. TI-Ie idlerrolls are spring-loaded to extend a slightly greater distance beyond thelumberconfronting edge of the movable fence sections. Thus when theopposing spring-loaded drive and idler rolls press against the oppositeedges of a piece of lumber within the defect-cutting station, they applyunequal forces against opposing edges of the lumber in a mannerresulting in the lumber being held against the fixed fences with apositive force. This ensures that the drivers will firmly engage thelumber to drive it through the defect station while at the same time thelumber will follow a true straight course as defined by the fixed fence.The driver rolls are driven by orbital motors 166 depending beneath therolls, one such motor being shown in FIG. 6.

The defect saws are covered by a removable overhead guard 168. Theoverhead guard also mounts a bracket 170 to which four photoelectricsensors [-5, H0, O-5, Q-10 are mounted. These photoelectric sensors andothers are illustrated elsewhere schematically by triangular symbols forsimplicity and clarity. Actually these sensors and others may be mountedanywhere on the apparatus where convenient. A fifth photosensor PC-4 ismounted behind and between the pair of defect saws on an upright supportmember 176 to detect defects between the saws. The functions of theseand other sensors are described subsequently.

Referring to FIG. -A, fixed fence 118 ends a shorter distance downstreamof the defect saws than corresponding movable fence 122. A stop bar 178continues downstream from the downstream end of the fixed fence. Threeair-actuated pop-out mechanical stops 180, 181, 182 are pinned to thestop bar at predetermined but adjustable positions along it to determinethe downstream ends of three specified long clear lengths which can becut from a piece using one of the two defect saws. In conjunction withthese mechanical stops, three end-of-piece photo sensors A-l, A-2, A-3are positioned along the stop bar upstream of the stops and operate inconjunction with a defect sensor PC-S upstream of the defect saws. Asecond set of three photoelectric end-of-piece sensors SA-l, SA-2, SA-3are positioned on the stop bar, one just in front of each popout stop toslow the drive rolls before a board reaches such stops. Finally amaximum length mechanical stopsensor 188 is adjustably positioned on thestop bar downstream of the pop-out stops to stop and control theprocessing of any piece that is not acted upon by the pop-out stops andhas no defect detected prior to reaching such stop.

FIG. shows one of the pop-out stops in detail. This typical pop-out stopincludes a stop body 190 adjustably connected to stop bar 178 by a pairof removable pins 191 extending through a pair of openings 192 in thestop body and through an aligned pair of stop bar openings 193. Anupwardly extending portion 194 of the stop body pivotally mounts an aircylinder 195 via pivot pin 196. The air cylinder has a piston rodportion 197 pivotally connected at 198 to a pop-out stop lever 199. Thestop lever is pivoted to the stop body at 200. Thus when the aircylinder extends, the piston rod 197 pivots stop lever 199 downwardlyand outwardly to a horizontal position 199a in the path of lumberpassing downstream through the defect station.

Referring to FIG. 6, the defect-cutting station includes an associatedsorting and transfer means. Such means includes inclined slideways 202,204 which merge at their upper ends at a primary diverter or flipflopgate 206. This gate determines onto which slideway a piece will dropwhen released from the defectcutting station through retraction of themovable fence sections.

The transfer slideway 202 leads to cut-to-length station 22. The sortingslideway 204 leads to a series of sorting stations to which pieces fromthe defect station are directed according to length or condition withoutpassing them through the cut-to-length station. Sorting slideway 204includes a pair of sorting gates 208, 209 leading respectively when opento conveyor belts 210, 21 1. Pieces sliding down the slideway 204 withboth diverter gates 208 and 209 closed will proceed onto a third,transfer belt 212. Thus, for example, defective sections cut from apiece can be diverted to a junk sort by belt 210 by positioningflip-flop arm 206 in its righthand position and gate 208 in its openposition. Similarly, clear pieces too short to be dropped to the cut-to-Iength station can be diverted to a core block sort on belt 211 bykeeping gate 208 closed but opening gate 209. As a further example, longclear pieces cut to length at the defect station can be diverteddirectly to a sorting station without passing to the cut-to-lengthstation by positioning flip-flop gate 206 in its right-hand position andby closing gates 208 and 209 so that the long clear pieces drop ontotransfer belts 212.

Operation at Defect Station Summarizing the processing of lumber at thedefect station, screw transfer rolls crowd a piece of lumber with markeddefects against fixed fence 86. When the defect infeed nip rolls areclear of the preceding piece and piece-present sensor PC-6 detects thepresence of a piece at the fence 86 and between nip rolls 90, the niprolls close, feeding lumber endwise through gate 94 and toward defectsaws 138, 139. At the same time movable fence sections and 122 moveinwardly to support the piece as it travels downstream in the defectstation and to press the piece against the fixed fence sections anddrive rolls 162. When photoelectric sensor PC-4 detects a marked defecton the piece between the saws, a signal from the sensor stops driverolls 162 and the driven nip roll 90 and extends air cylinders 158 tostroke defect saws 138, 139 simultaneously to cut the defective sectionfrom the piece. This defective section drops from between the saws alongslideway 204 through open gate 208 onto belt 210 where it is conveyed tothe junk sort.

The remaining clear piece downstream of the defect saws is measured by apair of outfeed photo sensors spaced apart a short distance downstreamof the saw 139 including a junk sensor 0-5 and a core block sensor 0-10.If such downstream piece is longer than, say, 10 inches, it is divertedto the cut-to-length saw station.

If such piece is within the range of, say, from 5 to 10 inches in lengthor as otherwise determined by spacing between the two sensors, it isdiverted to the core block sorting station by opening gate 209. If,shorter than 5 inches or any other predetermined minimum length asdetermined-by sensor -5, such piece is diverted to junk via open gate208.

An identical pair of infeedsensors, including a junk sensor and a coreblock sensor l-l0, measure and divert the remaining piece upstream ofthe saws in the same manner as the outfeed' sensors except that upstreampieces longer than inches or some other predetermined length resumetheir travel downstream toward the defect saws for processing aspreviously describedthrough reactivation of nip rolls 90 and drive rolls162'.

A piece having an exceptionally long clear length as measuredfrom itsleading end can be cut to one of three specified long lengths at thedefect-cutting sta- A-l, A-2, A-3 downstream of the saws. For example,if

a piece moving past the defect saws has its leading end sensed by sensorA-l but not sensors 'A-2 and A-3 as defect sensor PC-5 detects a defect,the associated electrical control circuit causes the air cylinder ofpopout stop 180 to extend and set such stop to block downstream travelof the piece when it reaches such stop. As the piece approaches stop180, sensor SA-l slows drive rolls 162 and nip roll 90. When the leadingend of the piece reaches set stop 180, the drive rolls stop and only thesecond .defect saw 139 strokes-to cut the piece to the shortest one ofthe three'specified long lengths. The movable fences retract and thegates are set to drop the long clear piece onto belt 212 to convey it toa long length sorting station, bypassing the cut-to-length station.

In a similar manner the activation of sensor PCS and both A-1 and A-2would set stop 181, and the activation of sensor PC-5 with all threestops A-l, A-2, A-3 would set stop 182. The end-of-piece sensors andtheir corresponding stops can be adjusted to various positions along thestop bar to provide various specified long lengths. Also a fewer orgreater number of pop-out stops and corresponding sensors couldbe'provided as desired to meet the needs of the user.

Cut-to-Length Station As shown in FIG. 6, cut-to-length station 22 ispositioned below and to one side of the defect-cutting station. Aspreviously mentioned, pieces cut to random clear lengths at the defectstation are dropped along slideway 202 to the cut-to-length station.

A piece arriving at the cut-to-length station is supported at about ainclination to the horizontal and on edge by lumber support meansincluding a pivotable bottom drop gate member 224 and a movablesidesupporting fence 226. As shown in FIG. 7, gate 224 is composed ofthree gate sections 224a, 224b, 2240 mounted for downwardly pivotingmovement on a common shaft 230 (FIG. 9). The fence and'drop gateposition a piece delivered to the cut-to-length station in the sectionsof drop gate 224 are fixed to long lengths of tubing 229 pinned tocommon shaft 230. The shaft is pivotally mounted in three sleevebearings 228 having supports 227 attached to a frame portion 231 of themachine. The drop gate sections are pivoted downwardly simultaneouslyfrom'a lumber-supporting posito the sorting area by an'air cylinder 232pivotally connected to a drop gate actuating arm 233.

A cut-to-length saw 234 is positioned along drop gate 224 and has acutting plane 234a extending normal to the length of the drop gate inthe gap between the drop gate sections 224a and 224b. With reference toFIG. 5,

it will be seen that length saw 234is insubstantial alignment with thedownstream saw 139. However, the cutto-length saw is offset justslightlydownstream from such defect saw so that random lengths droppinglater ally to the cut-to-length station from the defect station.

will have one end extending slightly into the cutting plane of lengthsaw 234. 1

Cut-to-length saw blade 234 is fixed to a shaft 235 carried on the outerend of a yoke arm 236. The yoke arm is pivoted at its inner end at 237to a support base 238. The pulley 239 fixed on shaft 235 is driven bydrive belt 240 from a secondpulley 241' on the drive shaft of anelectric motor 242. Yoke arm 236 pivots upwardly to move thecut-to-length saw through its cutting stroke by anair cylinder 244acting on a toggle linkage 246. The cutting stroke ofthe saw isindicated.

by dashed lines in FIG. 6.- t

Two pairs of nip-drive rolls, includingtwo inwardly movable idler rolls248 on fence 226, an' opposing fixed idler roll 249, and a single fixeddriven roll 250 are positioned along drop gate 224 formoving a piece atthe cut-to-length station endwise toward'and away from the cut-to-lengthsaw. The driven roll 250 is driven by an orbital motor 25l'mounted on asupport above the drive roll as shown in FIGS. 6 and 8.

A piece P dropped from the defect station to the cutto-length stationand supported on drop gate'224is pressed against the fixed drive rolls249, 250 'by idler rolls 248 which move inwardly to engage one side. ofthe piece with movable fence 226 under the influence of air cylinders(not shown). Drive motor 251 is reversible so that a piece can be drivenin either direction cut-to-length saw.

A stop-sensor bar 254, shown in FIGS. 7 and 9, is positioned downstreamof the cut-to-lengthsaw opposite fence 226 and along drop gate-sections224b and 224a. The stop bar 254 is mounted onframe member 231. A portionof the stop bar overhangs the drop gate and is provided with a series ofspaced-apart pin openings which provide for adjustable connection of aseries of stop-sensors SS at various distances from the saw 234 so as todetermine specified lengths towhich randomlength pieces will be cut bysuch saw. The stop bar also adjustably mounts a piece-present sensor PPwhich detects the presence of a piece of lumber at the cut-tolengthstation to trigger the actuation of the 'nipdrive rolls. One or morerandom-length sensors RS may also be mounted .on the stop bar'to dropcertain long random-length pieces from the cut-to-length station withoutcutting them to length.

The stop-sensors SS are adjustably secured to stop bar 254 by a pair ofremovable pins 257 extending through alinged pin openings in the stopbar and stopsensor. Referring to FIG. 11, the stop-sensor includes astop body 260 having an upper groove 261 receiving a depressible stoplever 262. The stop lever is pivoted at 263 to the stop body and isbiased outwardly by a spring 264 against the force of which the stoplever is depressible inwardly by a board force against the stop bar. Thelower portion of the stop body includes a pair of pin openings 265 whichreceive pins 257 for attaching the stop-sensor to the stop bar. For thispurpose the lower portion of the stop body includes agroove 266 intowhich the stop bar projects.

Stop body 260 also includes an air tube connector 269 for connecting anair tube from a pneumaticfluidie control panel (not shown). Theconnector leads into a drilled opening 267 in the body which connects toan air outlet 268 leading into the upper groove 261 of the body. Airentering the stop body is normally blocked by the stop lever 262 when inits normal released position. Thus nonnally the connected air tube willhave a high back pressure. However, when the lever is depressed by apiece of lumber, air can escape through outlet 268, producing a lowpressure in the connected air tube. However, when the stop lever isagain released, this will again block the escape of air from the stopbody, sending a pulse of high-pressure air to the pneumatic-fluidiccontrol circuit for a purpose to be described in conjunction with FIG.13.

The piece-present sensor PP and random-length sensor RS may be similarin construction to the stopsensor, except that in the former the stoplever and associated outer groove are eliminated and the air tubeconnector communicates with an air outlet passage extending completelythrough the sensor body to its lumber-engaging surface.

Below the cut-to-length station there is another sorting area (FIG. 6)where boards cut to length by the length saw are sorted according tolength. The sorting area includes two inclined slideways 270, 272.Slideway 270 includes a series of four diverter gates 274 selectivelypivotable upwardly on shafts 275 by aircylinders (not shown) to divertboards into one of four chutes or bins 276. Each chute leads to one oftwo driven side transfer belts 278, 279, which, when the machine is inoperation, continuously convey sorted material from the apparatus. Thesorting chutes are constructed in pairs, with each pair being formed bytwo outer walls 280, 281 and a vertical divider wall 282. An additionalseries of end transfer belts 284 convey pieces not diverted into one ofthe four chutes from the apparatus. The four gates 274 include a randomsorting gate 27411, a No. l sorting gate 274b, a No. 2 sorting gate2740, and a No. 3 sorting gate 274d.

Slideway 272 includes a junk gate 286 and a coreblock gate 288. Each ofthese gates is upstream of the cut-to-length saw, whereas the sortinggates 274 are downstream of such saw.

Operation at Cut-to-Length Station In operation a random-length clearpiece of lumber from the defect-cutting station longer than the minimumlength of, say, inches drops along slideway 202 onto closed drop gate224 with one end in alignment with the cut-to-length saw. Piece-presentsensor PP detects the piece and closes the drive-nip rolls, causing therolls and fence 226 to press one face of the piece against driven roll250 and stop-sensors on bar 254, depressing some or all of thestop-sensors, depending on the length of the piece. When this occurs,drive roll 250 rotates in a counterclockwise direction, driving thepiece endwise toward the cut-to-length saw. The piece continues towardsuch saw until the first one of the depressed stop sensors SS isreleased. Upon such release, drive roll 250 reverses to drive thedownstream end of the piece against the released stop. Then air cylinder244 extends to stroke the length saw 234, cutting the piece to aspecified length as determined by the released stop. Air cylinder 232then retracts, opening drop gate 224 and dropping the piece of specifiedlength into one of sorting chutes 276. The chute into which the piece isdiverted is determined by the released stop SS which, as soon asreleased, signals one of gates 274 to open through the pneumatic-fluidiccontrol circiut of FIG. 13.

A pair of sensors upstream of the cut-to-length saw, including a junksensor S-5 and a core block sensor S-l0, determine the length of theshort piece on that side of the saw. Pieces less than a minimum lengthof, say, 5 inches are diverted to junk through gate 286, whereas piecesbetween the minimum length and, say, 10 inches are diverted to the coreblock sort through diverter gate 288.

If a piece arriving at the cut-to-length station is less than theshortest specified length as determined by the position of the closeststop sensor -15 to the length saw, then piece-present sensor PP actsthrough the fluidic circuit to divert such short random-length piecedirectly to the random sort through gate 274a without stroking the saw.Additional adjustable random-length sensors such as sensor RS can bemounted on the stopsensor bar to cause lumber covering such stops butnot stop-sensors beyond such stops to be diverted to the random sortwithout saw operation.

The sensors on the stop-sensor bar are adjustable in short incrementsof, say, A inch. Each stop-sensor SS can be connected tofield-changeable connections in the pneumatic-fluidic control circuit insuch a way as to cause any selected one of the sorting gates 274 to openwhen a given stop-sensor is released.

Control Systems The control system of the illustrated embodiment isbroken down into two parts. First, an electrical control system shown inFIG. 12 controls the operation of the marking and defectsawing sectionsof the apparatus. Second, a pneumatic-fluidic control system shown inFIG. 13 controls the operation of the cut-to-length section and sortingtherefrom.

Electrical Control System Referring to the electrical control circuitryof FIG. 12, the portion of the circuit within bracket 300 representsmarking station operations controlled manually from operators station14. This portion of the circuit includes a series of manually controlledswitches including a flip switch 209, a center switch 291, a down switch292, and a feed switch 293. These four switches are opened and closedselectively by the operator using a four-way wobble stick control 302shown schematically in FIG. 14. With this stick the operator controlsactuation of flipper arms 44 at the infeed side of the marking stationand operation of the driven infeed nip roll 61. More specifically, withthe wobble stick in its down position, arms 44 assume their retractednearhorizontal position as shown in full lines in FIG. 2. With thewobble stick moved to its centered position, flipper arms 44 pivot totheir midway position 44a of FIG. 2 to tilt a board on-edge atapproximately a 60 angle to the horizontal. When the wobble stick movesto its flip position, flipper arms 44 pivot to their near-verticalposition 44b in FIG. 2 to turn a board over on skid rails 46. When thedesired face of a board is tilted toward the operator, movement of thewobble stick to its feed position activates the driven infeed nip roll60 at the marking station to feed a board toward marking nozzle 72. Inthe illustrated circuit, the fifth position of the wobble stick is notused but could be used if desired to activate the infeed drive 60 in areverse direction to help center a defect at the marking nozzle 72.

Time delay relay TDB in line 294 controls the time interval betweencommanding the flipper arms to their down position and their return totheir centered position 44a by closing contact TDB in line 295. Whenflip is commanded by the wobble stick, flip switch 291) moves downwardlyto close lines 296, 297, thereby extending both air cylinders 47 and 48in FIG. 2. With the wobble stick centered, center switch 291 closes inline 295, and as soon as relay TDB times out, its contact TDB in line295 also closes, thereby extending only air cylinder 47 to move flipperarms 44 to their midway positions 44a. With the wobble stick in the downposition, lines 304 and 304a are closed by upper throw of switch'292 toretract cylinders 47 and 48 and return flipper arms 44 to their loweredpositions.

A relay X in line 306a is a control relay which allows the infeed niprolls 60, 61 to remain closed if a piece of lumber is present betweensuch rolls and feed is commanded by the wobble stick. Sensor PC-l is aretroreflective photocell which senses lumber in the marking stationinfeed nip rolls and in response closes a normally open contact PC-l inline 306 to retract air cylinder 62 and thereby close the nip rolls. Aspring return on cylinder 62 opens the infeed nip rolls when contact P01is reopened by the absence of a piece between such rolls.

Retroreflective photocell PC-2 at the outfeed nip rolls 74, 75 of themarking station closes a corresponding contact PC-2 in line 308 when apiece is present between such rolls, thereby actuating an air cylinderto close the outfeed nip rolls. The outfeed nip rolls reopen via aspring return when a piece is no longer present between such rolls.

A retroreflective photocell PC-3 on the screw roll transfer table sensesthe presence of lumber on such table and closes a corresponding contactPC-3-in line 310 to energize a time delay relay TD-1. This relay timesout if photocell PC-3 is blocked longer than its setting to close relaycontact TD-l in line 3111a and thereby illuminate a warning light R onthe operator control panel to warn the operator that the transfer tableis full.

Photocell PC-4 is a retroreflective line scan photocell which senses amarked defect between the defect saws. When a defect is sensed,corresponding contacts PC-4 in lines 312, 315 close to energize singlecoil latching relays L-l and -L-2. These relays close correspondingcontacts L-l and L2 in lines 313, 316 to extend the air cylinders 158for the defect saws to stroke such saws simultaneously. Normally closedlatching relay contacts L-1 andL-2 in lines 314, 317 retract the defectsaw actuating cylinders to return the saws to their initial positions.

The portion of the circuit within bracket 318 represents an anticipatorcircuit which provides the control for cutting pieces to specified longclear lengths at the defectcutting station. This circuit includes apermanent magnet latch relay PML in line 319. A pulse through line 319acauses unlatching of the relay, whereas a pulse through line 31% causeslatching of the relay. The relay latches if the anticipator system is tobe used. In this regard a pulse from photocell PC-4 closes acorresponding contact PC-4 in line 319a to cause unlatching of therelay. On the other hand, a pulse from the retroreflective line scanphotocell PC-5 upstream from the defect saws closes a contact P05 inline 3191; to cause latching of the relay when it senses a markeddefect. This photocell is also used to control the screw roll transfertable off-feed nip rolls 90, although a separate photosensor PC-6 alsoserves this function.

A limit switch SW-l senses lumber at the defect saw outfeed drive roll.It has a contact SW-2 in line 3190 in parallel with a normally opencontact PC-4 in line 3190 which functions to control the resetting ofrelay PML. An additional switch contact SW-l in line 323b controls arelay 14A in line 323 which stops the motor for drive rolls 162 byclosing contact KA in line 327. A third contact SW-1 in line 338aenergizes time delayv relay TD-4 in line 338. This relay controls thetime allowed for the defect saws to stroke by delaying the retraction ofthe movable fence to drop a clear piece until after it times out toclose relay contact TD-4 in line 3411.

Sensors A-ll, A-2 and A-3 are retroreflective photocells positioned onthe outfeed side of the defect saws and at adjustable distancestherefrom for sensing the downstream end of a piece traveling downstreamthrough the defect station. These three sensors determine the maximumlength available for the long clear cut-to-length function of the defectstation. Latching of the PML relay in line 319 by photocell PC-5 closesa contact PML in line 326, energizing a time delay relay TDA formingpart of a one-shot system for the anticipator circuit. The closing ofthe PML contact also energizes a control relay C in line 326a, inparallel with the relay TDA. Relay C is an output control for theone-shot anticipator system and remains energized until relay TDA timesout to open contactDTA in line 326a. Energization of relay C closes acorresponding contact C in line 320. At this moment if the photocellA-ll senses the end of a board on the outfeed side of the defect saw butphotocells A-2 and A-3 do not, the corresponding contact A-l in line 320also closes, causing the air cylinder on the first pop-out stop toextend to set such stop and determine the specified long length to becut.

0n the other hand, if, at the time the PML relay is latched, bothphotocells A-1 and A-2 sense the downstream end of the piece,corresponding contacts A-1 and A-2 in line 321 close while thecorresponding contact A-2 in line 320 opens, thereby extending the aircylinder on the second pop-out stop 181 to set that stop and determine aslightly longer specified length to be cut.

A third line 322 with normally open sensor contacts A-Il, A-2 and A-3,all close when all three of the corresponding sensors detect thedownstream end of a piece at the same time sensor PC-S detects a markeddefect. This event also opens the contacts A-3 in lines 320 and 321 sothat only the third of the three pop-out stops 182 is set to determinethe longest of the three specitied clear lengths to be cut by the defectsaw.

Sensors SA-l, SA-2 and SA-3 are retroreflective photocells which detectthe end of a board as it approaches one of the stops and functions toslow the drive rolls 162 to slow down the lumber before it reaches theset mechanical stop. These sensor have corresponding normally opencontacts in line 324. When any one of such sensors senses a piece, itcloses its corresponding contact in line 324 to energize time delayrelay TD-2 which times out the deceleration period prior to stopping thelumber at the set mechanical stop. When relay TD-2 times out, it closesa contact TD-2 in line 323 thereby energizing a control relay KA. Thisrelay has a contact KA in line 327 which closes when the relay isenergized to stop drive rolls 162. Contacts PC-4 and SW-l in parallelwith contacts TD-2 in line 323 also serve this function.

A single coil latching relay K-l in line 325 is energized either when arelay contact KA is closed or a relay contact TD-6 is closed in the sameline. Relay TD-6 is a time delay relay in line 344 controlling the timeallowed for the defect saws to clear the piece before restarting driverolls 162. Relay [(-1 thus is controlled by the drive starbstop signalsand includes a corresponding contact K-l in line L to enable operationof the sorting gate circuitry.

Time delay relay TD-4 in line 338 can be energized either by closinglimit switch contact SW-l in line 338a or by closing relay contact K-lthrough its corresponding latching relay K-l in line 325. When timedelay relay TD-4 times out, it closes contact TD-4 in ine 328 to retractthe air cylinder on the set one of the three pop-out stops.

A time delay relay TD-3 in line 329 controls the spacing between piecesof lumber fed into the defect station by the nip rolls 90. It controlsthe spacing by controlling the delay in reopening of infeed nip rolls90. Relay TD-3 is energized when a contact PC-S in line 329 closes. Thiscontact is closed by the corresponding photocell PC-S. When relay TD-3times out, it closes contact TD-3 in line 330 to open nip rolls 90.

The piece-present sensor PC-6 is also a retroreflective photocell whichfunctions to reclose nip rolls 90 when a piece is present at the fenceon the screw roll table by closing sensor contact P06 in line 331.

The remaining portion of the circuit controls the sorting from thedefect station. As previously mentioned, it is necessary for thefunctioning of the sorting circuit for the normally open gate set-upcontrol contact K-l in line L to be closed by relay K-l in line 325,which can only occur when drive rolls 61 are stopped.

Two outfeed sensors -5 and O-l0 are retroreflective photocells whichmeasure a piece at inches an 10 inches, respectively, downstream fromthe downstream defect saw 139. Sensor 05 has normally open contacts O-5in lines 332 and 333 and a normally closed contact O5 in line 334.Outfeed sensor L-I0 has a normally open contact in line 332 and normallyclosed contacts in lines 333 and 334. Thus if both sensors O-S and O-l0sense the piece, indicating a piece longer than 10 inches on the outfeedside of the defect saws, contacts O-S and O-10 in line 332 close toactuate the flip-flop gate 206 in FIG. 6 to a position for diverting thepiece to the cut-to-length station. On the other hand, if only sensorO-5 senses the piece, line 332 remains open and line 334 is open, butline 333 closes, energizing control relay K-2. This relay closes relaycontact K-2 in line 335a to close line 335 and position the flip-flopgate to divert the piece to the core block or junk sort. At the sametime another relay contact K-Z in line 336 closes to open core blockgate 209.

Similarly, if a piece on the outfeed side of the defect saws is lessthan 5 inches, neither lines 332 or 333 close, but line 334 remainsclosed, energizing relay K-3 which closes relay contacts K-3 in lines335 and 337 to divert'the short piece to junk, the line 337 controllingthe junk sort gate.

The similar retroreflective photocell sensors l-S and H0 at the infeedside of the defect saws measure pieces at 5 inches and 10 inches,respectively, from upstream defect saw 138. If the piece upstream of thedefect saws is shorter than 5 inches so that neither photocell isactivated, the normally closed contacts in line 339 and 339a remainclosed to open infeed junk gate 208. However, if the sensor l-5 isenergized, the contact [-5 in line 339a opens and the contact I-5 inline 339 closes, opening infeed core block gate 209.

Now, however, assuming that the piece remaining upstream of the defectsaws is so long that it energizes both sensors I-5 and I-10 indicatingthat its length is greater than 10 inches, neither the infeed core blockgate nor the infeed junk gate opens, and contacts l-5 and [-10 in lines346 and 346a open to prevent retraction of the short movable fence andrelease of the piece to the sorting area. In the meantime, time delayrelay TD-6 times out and drive rollers 162 restart to feed the pieceinto the defect saws.

Time delay relay TD-4 in line 338 controls the time allowed for thedefect saws to stroke before the movable fence retracts to drop thepiece. Time delay relay TD-5 in line 341 controls the time allowed forthe movable fences to operate. When relay TD-4 times out, it closescontact TD-4 in line 340 to retract the long movable fence 122 and dropthe cut piece to the cut-tolength station. At the same time it closescontact TD-4 in line 341 to energize time delay relay TD-5. When relayTD-S times out, it closes contacts TD-5 in lines 342 and 343 to extendthe short and long movable fences 120, 122. The timing out of this relayalso closes contact TD-S in line 344 to energize relay TD-6. When relayTD-6 times out, it closes contact TD-6 in lines 345, 34511 to restartdrive rolls 162.

The retroreflective photocells are complete units including lightsource, pick-up, amplifier and output relay. The line scan photocellsare complete with power supply, amplifier and relay. Both types ofphotocells are well known and readily commercially available.

Pneumatic-Fluidic Control System Referring to the control logic diagramof FIG. 13, a pneumatic-fluidic control system is used for controllingthe operation at the cut-to-length station and the sorting which takesplace from the cut-to-length station.

The circuit includes an air supply line 360 supplying air to each of the15 stop-sensors SS-l through SS-lS positioned along stop-sensor bar 254and also to piecepresent sensor PP and random-length sensor RS on thebar. All these sensors are on one side of the cutting plane 234a of thecut-to-length saw. The air supply line also supplies air to twomeasuring sensors SS-S and SS-10 on the opposite side of thecut-to-length saw.

From the construction of a typical stop-sensor SS as shown in FIG. 11,it will be seen that when the depressible stop lever of each stop-sensoris in its released position, there will be a relatively highbackpressure in the various input lines 361 leading to the various pairs ofinput one-shot gates M-l through M 4. This is the normal condition ofthe circuit when there is no board present at the cut-to-length station.

However, with no board present, random-length sensor RS, piece-presentsensor PP and core block and junk-measuring sensors S- and S-10, all ofwhich are normally open to atmosphere when unblocked, induce arelatively low back pressure in their input lines 362, 363, 364, 369,respectively, leading to their respective input gates M-6, M-8, M'-9When a board arrives at ,the cut-to-length station normally blocking atleast piece-present sensor PP and the random-length sensor RS, arelatively high back pressure is induced in their respective input lines362, 363. Of course, when sensors S-5 and S-l0 are blocked, there is ahigh back pressure output from these sensors also to their respectiveinput gates.

However, when a board is pressed against the stopsensors SS to depresstheir stop levers, a low pressure pulse is induced in their input lines361. When one of the stop-sensors SS is released again, its input line361 transmits a high pressure pulse.

The illustrated control-circuit includes ten series of NOR gates M-lthrough M- interconnected in-such a manner with each other and connectedto the various stop-sensors, random sensors and other sensors to operatethe various elements at the cut-to-length station in the mannerpreviously described under the heading Operation at Cut-to-LengthStation..

In addition to the NOR gates, the circuit includes three sorting gatemanifolds 365, 370, 374. Manifold 365 controls the air supply throughline 366 to a No.

1 sorting gate flip-flop circuit 367 which controls the I opening andclosing of the No. 1 sorting gate 274a through controlling theshiftingof a No. 1 gate cylinder operating valve 368.

Manifold 370 controls the air supply to a second flipflop circuit 367athrough line 371 to control the shifting movement of the No. 2 sortinggate cylinder operating valve 372. v

The third gate manifold 374 controls the supply of air through a line375 to a third sorting gate flip-flop circuit 367b which controls theoperation of the No. 3 sorting gate cylinder operating valve 376.

Lines 377 from each of the three sorting gate mani folds lead to a CTLflip-flop circuit 378 which controls signals to a drive reverse timingcontrol one-shot circuit 380, including a variable time D-4 and a pairof gates M-7. The CTL flip-flop circuit also controls the signal to asaw stroke time delay D-3, to saw stroke one-shot gates M-7 at 382, andto the CTL drive motor control valve 384. Signals from the saw strokeone-shot gates 382 are transmitted to a saw single stroke steerableflip-flop circuit 386 controlling the operation of the sawstroke controlvalve 388.

Because there are only three sorting gates which sort material to lengthbut a total of stop-sensors, the sensors are arranged in the circuit sothat sensors SS-l, SS-5, SS-9 and SS-l3, that is every fourth sensor,lead to manifold 365 so as to sort into the No. l sorting gate.

Then sensors SS-2, SS-6 and so forth sort into the No. 2 sorting gate,and sensors SS-3, SS-7 and so forth sort into the No. 3 sorting gate.Sensors SS-'4, SS-8 and SS-l2 then can be arranged to either sort intothe random sorting gate, not shown in the circuit, or connected so asnot to actuate any of the gates whereby they are carried off on thetransfer belts 284. In any event, the input gates for the sensors SS-4,SS-8, SS-l2 are connected so as to transmit a signal into the CTLflip-flop circuit 378 in a manner, for example, shown with respect tothe stop-sensor SS-8, which is typical of the way in which the inputgates from sensors SS-4 and SS-l2 would also be connected.

When random-length sensor RS is covered but downstream sensors SS-l2,SS-l3, etc., are not depressed, a high pressure air pulse is transmittedfrom randomlength sensor RS through input line 362 to a series of threegates M-6. These gates transmit a signal to a random-length flip-flopcircuit 390 including a pair of gates M-8 which, in conjunction withdownstream pairs of gates M-8 and M-7, maintain the CT L drive motorvalve 384 in its neutral position so that the CTL drive does notoperate. At the same time a signal shifts control valve 392 to operatethe CTL drop gate and drop the random piece to its sorting area.

The piece-present sensor PP, when blocked, transmits a high pressuresignal through line 363 to piecepresent flip-flop circuit 394 includinga pair of gates M-8, which controls the operation of a CTL fence controlvalve 396 and a fence-extend time delay D-l. At the same time a line 397leading from sensor SS-l5, under high pressure when sensor SS-l5 is notdepressed, leads to a series of three short length random control gates398. These gates produce a signal which shifts the CTL drop gate valve392 in a direction for opening the drop gate when only the piece-presentsensor is blocked and none of the stop-sensors are de- I pressed. Thesecontrol gates'also control the operation of a piece drop time delay D-2.

Further down the diagram of FIG. 13, measuring sensors S-5 and S-10,when blocked, transmit a high pres sure pulse through a series of inputgates M-9 to a junk gate flip-flop circuit 400 in the case of sensor S-5and to a core block flip-flop circuit 402 in the case of sensor S-l0.Flipflop circuit 400 controls the operation of a CTL junk gate cylinderoperating valve 404. Flip-flop circuit 402 controls the operation of avalve .406 for controlling the operation of the corefblock gatecylinder.

In typical operation of the logic circuit to cut a board to length,assume that a long, clear, random-length board drops to thecut-to-length station and is long enough to cover all of thel5'stop-sensors from 88-1 through SS15. First the board .blockspiece-present sensor PP, sending a high pressure signal to the flip-flopgates 394 and resulting in a high pressure signal to the extend side ofthe CTL fence-operating valve to shift the valve, whereby fence 224 andthe drive-nip rolls press the board against the CTL stop bar 254,depressing all of the stop-sensors SS-l through SS-15. At this time thestop-sensor input gates place the manifolds 365, 370, 374 under lowpressure, closing the three sorting gates. The low pressure also causesCTL flipflop circuit 378 to transmit a low pressure signal to the inputside of the gate M-7 leadingto the CTL drive motor control valve 384whereby such gate transmits a high pressure output to the forward sideof valve 384, causing the CTL drive roll to-operate in a direction tofeed the board endwise toward the saw cutting plane 234a. This endwisetoward movement continues until stop SS-l is released.

When stop-sensor SS-l releases, its input gates M-l send a high pressuresignal into manifold 365 causing the No. 1 sorting gate valve 368 toshift top open the No. 1 sorting gate. At the same time, a high pressuresignal from manifold 365 causes a high pressure input into the CTLflip-flop circuit 378, resulting in a high pressure input signal at thedrive reverse timing oneshot 380 to shift the CTL drive motor valve 384to its reverse position, reversing the direction of the CTL drive roll,and at the same time actuating the drive reverse timer D-4 and the sawstroke time delay D-3. Thus the board is driven back against thereleased stop lever of stop-sensor 85-1 and the CTL drive motor stopswhen timer D-4 times out. Thereafter time delay D-3 also times out,whereby the saw stroke one-shot 382 transmits a signal to saw strokesteerable slip-flop 386 which actuates the saw stroke operating valve388 to stroke the saw. Thus the boardis cut to specified length asdetermined by the distance of stop-sensor SS-l from the cutting plane234a.

After the CTL saw strokes, piece drop time delay D-2 times out,permitting the CTL drop gate valve 392 to shift to open the drop gate,dropping the cut-to-length piece through the open No. 1 sorting gate.When the piece drops from the cut-to-length station, all of the stopsare cleared and the piece-present sensor is opened causing the CTL fenceto retract and the CTL drop gate to reclose to await arrival'of the nextpiece.

With the foregoing description of the operation of i the circuit, thoseskilled in the art should be able to' trace the operation of the circuitfor other lengths of boards, including short boards which cover only thepiece-present sensor and longer boards extending only to random sensorRS. Under both mentioned conditions, the CTL drop gate opens without thedrive motor operating and without the saw stroking.

Having illustrated and described a prototype of my invention and what isnow a preferred embodiment thereof, it should be apparent to thoseskilled in the art that the same permits of modification in arrangementand detail. It will be apparent, for example, that various types ofcontrol circuits may be employed other than the typical electrical andfluidic circuits illustrated. It will also be obvious that various othersorting and transfer arrangements could be used and that limit switchescould be used in many instances instead of photosensors. It may also bedesirable in certain instances to increase the speed of production byproviding two cut-to-length stations to which pieces are fed alternatelyfrom the defect-cutting station. In any event, I claim as my inventionall such modifications coming within the true spirit and scopeof thefollowing claims.

I claim:

1. Apparatus for clear-cutting lumber to random and specified lengthscomprising in combination:

a defect-cutting station including defect-cutting means,

means for driving a piece of lumber endwise across the cutting plane ofsaid cutting means, means for sensing a defect in said piece at saidcutting means, and means for actuating said cutting means to remove thesensed defect in response to said defectsensing to provide a randomclear length of lumber,

means for transferring said randomclear length from said defect-cuttingstation to a cut-to-length station,

said cut-to-length station including length-cutting means, means forsensing the longest specified length in a given clear random-lengthpiece, and means responsive to a specified-length sensing forpositioning said clear random length with respect to said length-cuttingmeans so as to enable said length-cutting means to cut said randomlength to the longest specified length sensed, and means operable toactuate said length-cutting means in response to the positioning of saidrandom length.

2. Apparatus according to claim 1 including lengthsensing means at saiddefect-cutting station for sensing a specified long clear length in apiece and means including said driving means and stop means downstreamof said cutting means operable in response to a sensing of saidlength-sensing means for positioning said piece with respect to saiddefect-cutting means for cutting said piece to said specified long clearlength and for actuating said defect-cutting means in response topositioning of said piece for cuttingto said length.

3. Apparatus according to claim 1 including means at said defect-cuttingstation for sensing a random clear length less than a specified shortclear length and means operable in response to said short-length sensingfor diverting said random short clear length from said defect-cuttingstation to a collection point remote from said cut-to-length station.

4. Apparatus according to claim 1 wherein said defect-cutting meansincludes a pair of closely spacedapart defect-cutting elements havingparallel cutting planes extending nonnal to the path of travel of lumberat said defect-cutting station, said cutting elements being operableautomatically in unison in response to a defect-sensing to cut adefective section from said lumber and at least one of said elementsbeing operable singly in response to a sensing of a specified long clearlength downstream of said one element to cut a clear piece of lumber tosaid specified length.

5. Apparatus according to claim 4 wherein said defect-sensing means ispositioned for sensing the presence of a defect between said pair ofcutting elements and is operable as part of a control means todeactivate said driving means and activate said cutting elementssimultaneously in response to a defect sensing.

6. Apparatus for clear-cutting lumber to random and specified lengthscomprising in combination:

a defect-cutting station including defect-cutting means,

means for driving a piece of lumber endwise across the cutting plane ofsaid cutting means, means for sensing a defect in said piece at saidcutting means, and means for actuating said cutting means to remove thesensed defect in response to said defectsensing to provide a randomclear length of lumber,

means for transferring said random clear length from said defect-cuttingstation to a cut-to-length station,

said cut-to-length station including length-cutting means, means forsensing the longest specified length in a given clear random-lengthpiece, and

means responsive to a specified-length sensing for positioning saidclear random length with respect to said length-cutting means so as toenable said length-cutting means to out said random length to thelongest specified length sensed, and means operable to actuate saidlength-cutting means following the positioning of said random length,

said means for transferring including an inclined slideway extendingdownwardly between said defectcutting station and said cut-to-lengthstation, and movable lumber-support means at said defect-cutting stationoperable in response to a defect-cutting to drop a resulting randomclear length of lumber onto said slideway.

7. Apparatus according to claim 1 including sorting means downstream ofsaid cut-to-length station for sorting to length clear pieces from saidcut-to-length station, said sorting means including an inclined slidewaymeans leading downwardly from said cut-to-length station, said slidewaymeans including multiple sorting gates for diverting specified lengthsto a series of sorting stations, said sorting gates being selectivelyoperable in response to specified-length sensings at said cutto-lengthstation.

8. Apparatus according to claim 1 including a marking station upstreamof said defect-cutting station including means for marking defects witha sensitive material Capable of being sensed by said sensing means atsaid defect-cutting station.

9. Apparatus according to claim 8 including transfer means between saidmarking station and said defectcutting station including means fortransferring pieces of lumber first endwise from said marking station,then edgewise, then endwise again into said defect-cutting station.

10. Apparatus according to claim 1 including a marking station upstreamfrom said defect-cutting station including means for marking defectswith a sensitive material to which said defect-sensing means isresponsive,

sorting means downstream from said cut-to-length station for sortingclear-cut pieces to length,

and transfer means between said marking station and said defect-cuttingstation and between said defectcutting station and said cut-to-lengthstation for transferring pieces between said stations.

lll. Apparatus according to claim 10 wherein there is primarily endwisetransfer of pieces through said marking station and to saiddefect-cutting station and primarily edgewise transfer of pieces fromsaid defectcutting station to said cut-to-length station and from saidcut-to-length station to said sorting means.

12. An apparatus for cutting lumber to random or specified clear lengthscomprising:

means for conveying lumber endwise along a linear path,

a pair of closely spaced-apart defect-cutting means having parallelcutting planes extending across said path,

defect-sensing means for sensing the presence of a defect between saidpair of cutting means,

means for actuating said pair of cutting means simultaneously inresponse to a defect sensing to cut a defective section from said piece,

and means for actuating one of said pair of cutting means singly to cuta clear portion of a piece extending downstream of said one cuttingmeans to a specified clear length.

13. Apparatus according to claim 12 including means for deactivatingsaid conveying means in response to a defect sensing so as to positionthe sensed defect between said pair of cutting means. I

14!. Apparatus according to claim 12 including lumber support means forsupporting a piece of lumber in said path and movable away from asupported lumber piece following activation of said pair of cuttingmeans to divert the supported piece laterally downwardly from said pathunder the influence of gravity.

15. Apparatus according to claim 14 including an inclined sortingslideway means and an inclined transfer slideway means declined inopposite directions below said lumber support means and diverter meansat the juncture of said slideways operable following a cutting operationfor diverting lumber sections dropped from said path onto one or theother of said slideway means.

16. Apparatus according to claim 12 including infeed means at an infeedend of said linear path upstream of said cutting means including sensormeans for sensing the presence of a piece of lumber at said infeed endand means engageable with said piece in response to a presence sensingof said sensor means for conveying said piece endwise toward saiddefect-cutting means along said path.

17. Apparatus according to claim 12 including length-sensing meansdownstream of said cutting means for measuring a specified minimumlength of lumber extending downstream of said cutting means and meansfor diverting lengths greater than said specified minimum length fromsaidpath to a second cutting station and for diverting lengths less thansaid specified minimum length to a sorting means removed from saidsecond cutting station.

18. Apparatus according to claim 17 including second length-sensingmeans upstream of said cutting means for measuring a specified minimumlength of lumber extending upstream of said cutting means and meansoperable to divert upstream lengths less than said specified minimumupstream length from said path to said sorting means removed from saidsecond cutting station and operable to convey upstream lengths greaterthan said specified minimum upstream length along said path toward saidcutting means for processing by said defect-sensing and -cutting means.

19. An apparatus for cutting lumber to random or specified clear lengthscomprising:

means for conveying lumber endwise along a linear path,

a pair of closely spaced-apart defect-cutting means having parallelcutting planes extending across said path,

defect-sensing means for sensing the presence of a defect between saidpair of cutting means,

means for actuating said pair of cutting means simultaneously inresponse to a defect sensing to cut a defective section from said piece,

means along said path for sensing a specified long clear length in agiven piece of lumber,

and means including said conveyor means operable in response to aspecified long-length sensing for positioning said piece with respect toone of said pair of defect-cutting means and for actuating said onedefect-cutting means in a manner to cut said piece to the specified longclear length sensed.

20. Apparatus according to claim 19 wherein said specified long clearlength-sensing means includes means for sensing the longest of multiplespecified long clear lengths and wherein said means operable in responseto said sensing includes means for positioning said piece with respectto said one cutting means in a manner so as to cut from said piece thelongest clear length sensed.

21. Apparatus according to claim 19 including means operable to divertrandom clear lengths less than said specified long clear length to acut-to-length cutting station and for diverting clear lengths cut tosaid specified long clear length to a collection point removed from saidcut-to-length station.

22. Apparatus according to claim 19 wherein said long clearlength-sensing means includes a defect sensor along said linear pathupstream of said pair of cutting means and at least one end-of-piecesensor along said path downstream of said cutting means for sensing theleading end of a piece, with the distance between said upstream defectsensor and said downstream endof-piece sensor determining said longspecified clear length, said long clear length-positioning meansincluding a stop means positioned downstream of said end-ofpiece sensorand spaced from said one cutting means a distance corresponding to saidspecified long clear length.

23. Apparatus according to claim 22 including a plurality ofend-of-piece sensors spaced along said linear path downstream of saidpair of cuttingmeans determining a plurality of specified long clearlengths and a plurality of extendible stops downstream of saidend-ofpiece sensors, each stop corresponding to a different one of saidend-of-piece sensors, and means operable in response to a sensing of thelongest specified clear length to extend the corresponding one of saidstops into said path to determine the cutting position of a piecedownstream with respect to said one defectcutting means to enablecutting the longest specified clear length sensed.

24. An apparatus for cutting lumber to random or specified clear lengthscomprising:

means for conveying lumber endwise along a linear path,

a pair of closely spaced-apart defect-cutting means having parallelcutting planes extending across said path,

defect-sensing means for sensing the presence of a defect between saidpair of cutting means,

means for actuating said pair of cutting means simultaneously inresponse to a defect sensing to cut a defective section from said piece,

first measuring means for measuring a specified minimum cut lengthextending downstream from said pair of cutting means and means fordiverting random lengths greater than said specified minimum length fromsaid linear path to a cut-to-length cutting station and for divertingrandom lengths less than said specified minimum length to a collectingstation bypassing said cut-to-length station,

second measuring means for measuring a minimum cut length extendingupstream from said cutting means and means for diverting upstreamlengths less than said specified minimum upstream length from said pathto a collection station bypassing said cut-to-length station and forreactivating said conveyor means to convey upstream lengths greater thansaid minimum specified upstream length along said path toward said pairof cutting means,

third measuring means for measuring a specified long clear length in apiece of lumber extending from the leading end of said piece, and meansoperable in response to a measurement of said specified long clearlength in a piece for positioning said piece with respect to one of saidpair of cutting means so that the specified long clear length extendsdownstream from said one cutting means and for activating said onecutting means only to cut said specified long clear length from saidpiece.

25. An apparatus for cutting lumber to specified lengths comprising:

length-cutting means defining a cutting plane,

stop bar means extending normal to said cutting plane and including aseries of programmable depressible stop and length-sensing means spacedat predetermined distances from and on one side of said cutting planecorresponding to specified lengths of lumber to be cut,

means for delivering a random length of lumber to a position extendingalong said stop bar means with one end of said piece adjacent saidcutting plane,

drive means for pressing said piece toward said stop bar means todepress one or more of said stop and sensing means and for driving saidpiece endwise in opposite directions along said stop bar means,

and control means operable in response to the presence of said piecealong said stop bar means first to operate said drive means in onedirection to drive said random length toward said cutting plane until adepressed one of said stop and sensing means is released and then inresponse to such release to reverse said drive means to drive theopposite end of said random length against said released stop means andthen to actuate said cutting means to cut said random-length piece tothe longest specified length as sensed by said stop and sensing means,

said length-cutting means being at a length-cutting station andincluding:

a defect-cutting station above said length-cutting station,

said defect-cutting station including defect-cutting means operable tocut defective sections from a length of lumber to produce clear piecesof random length,

said defect-cutting means including a defect-cutting plane determiningone end of a clear piece and being in approximate vertical alignmentwith said length-cutting plane,

said delivering means including inclined slide means extending betweensaid defect-cutting station and said length-cutting station,

and movable lumber-support means at said defectcutting station movablefrom a support position above said slide means for supporting lumber atsaid defect-cutting station in parallel relation to the supportedposition of lumber at said length-cutting station, to a release positionfor dropping a clear piece from said defect-cutting station onto saidslide means for sideways gravity delivery to said length-cuttingstation.

1. Apparatus for clear-cutting lumber to random and specified lengthscomprising in combination: a defect-cutting station includingdefect-cutting means, means for driving a piece of lumber endwise acrossthe cutting plane of said cutting means, means for sensing a defect insaid piece at said cutting means, and means for actuating said cuttingmeans to remove the sensed defect in responSe to said defect-sensing toprovide a random clear length of lumber, means for transferring saidrandom clear length from said defect-cutting station to a cut-to-lengthstation, said cut-to-length station including length-cutting means,means for sensing the longest specified length in a given clearrandom-length piece, and means responsive to a specified-length sensingfor positioning said clear random length with respect to saidlength-cutting means so as to enable said lengthcutting means to cutsaid random length to the longest specified length sensed, and meansoperable to actuate said length-cutting means in response to thepositioning of said random length.
 2. Apparatus according to claim 1including length-sensing means at said defect-cutting station forsensing a specified long clear length in a piece and means includingsaid driving means and stop means downstream of said cutting meansoperable in response to a sensing of said length-sensing means forpositioning said piece with respect to said defect-cutting means forcutting said piece to said specified long clear length and for actuatingsaid defect-cutting means in response to positioning of said piece forcutting to said length.
 3. Apparatus according to claim 1 includingmeans at said defect-cutting station for sensing a random clear lengthless than a specified short clear length and means operable in responseto said short-length sensing for diverting said random short clearlength from said defect-cutting station to a collection point remotefrom said cut-to-length station.
 4. Apparatus according to claim 1wherein said defect-cutting means includes a pair of closelyspaced-apart defect-cutting elements having parallel cutting planesextending normal to the path of travel of lumber at said defect-cuttingstation, said cutting elements being operable automatically in unison inresponse to a defect-sensing to cut a defective section from said lumberand at least one of said elements being operable singly in response to asensing of a specified long clear length downstream of said one elementto cut a clear piece of lumber to said specified length.
 5. Apparatusaccording to claim 4 wherein said defect-sensing means is positioned forsensing the presence of a defect between said pair of cutting elementsand is operable as part of a control means to deactivate said drivingmeans and activate said cutting elements simultaneously in response to adefect sensing.
 6. Apparatus for clear-cutting lumber to random andspecified lengths comprising in combination: a defect-cutting stationincluding defect-cutting means, means for driving a piece of lumberendwise across the cutting plane of said cutting means, means forsensing a defect in said piece at said cutting means, and means foractuating said cutting means to remove the sensed defect in response tosaid defect-sensing to provide a random clear length of lumber, meansfor transferring said random clear length from said defect-cuttingstation to a cut-to-length station, said cut-to-length station includinglength-cutting means, means for sensing the longest specified length ina given clear random-length piece, and means responsive to aspecified-length sensing for positioning said clear random length withrespect to said length-cutting means so as to enable said length-cuttingmeans to cut said random length to the longest specified length sensed,and means operable to actuate said length-cutting means following thepositioning of said random length, said means for transferring includingan inclined slideway extending downwardly between said defect-cuttingstation and said cut-to-length station, and movable lumber-support meansat said defect-cutting station operable in response to a defect-cuttingto drop a resulting random clear length of lumber onto said slideway. 7.Apparatus according to claim 1 including sorting means downstream ofsaid cut-to-length station for sorting to length clear pieces from saidcut-to-Length station, said sorting means including an inclined slidewaymeans leading downwardly from said cut-to-length station, said slidewaymeans including multiple sorting gates for diverting specified lengthsto a series of sorting stations, said sorting gates being selectivelyoperable in response to specified-length sensings at said cut-to-lengthstation.
 8. Apparatus according to claim 1 including a marking stationupstream of said defect-cutting station including means for markingdefects with a sensitive material capable of being sensed by saidsensing means at said defect-cutting station.
 9. Apparatus according toclaim 8 including transfer means between said marking station and saiddefect-cutting station including means for transferring pieces of lumberfirst endwise from said marking station, then edgewise, then endwiseagain into said defect-cutting station.
 10. Apparatus according to claim1 including a marking station upstream from said defect-cutting stationincluding means for marking defects with a sensitive material to whichsaid defect-sensing means is responsive, sorting means downstream fromsaid cut-to-length station for sorting clear-cut pieces to length, andtransfer means between said marking station and said defect-cuttingstation and between said defect-cutting station and said cut-to-lengthstation for transferring pieces between said stations.
 11. Apparatusaccording to claim 10 wherein there is primarily endwise transfer ofpieces through said marking station and to said defect-cutting stationand primarily edgewise transfer of pieces from said defect-cuttingstation to said cut-to-length station and from said cut-to-lengthstation to said sorting means.
 12. An apparatus for cutting lumber torandom or specified clear lengths comprising: means for conveying lumberendwise along a linear path, a pair of closely spaced-apartdefect-cutting means having parallel cutting planes extending acrosssaid path, defect-sensing means for sensing the presence of a defectbetween said pair of cutting means, means for actuating said pair ofcutting means simultaneously in response to a defect sensing to cut adefective section from said piece, and means for actuating one of saidpair of cutting means singly to cut a clear portion of a piece extendingdownstream of said one cutting means to a specified clear length. 13.Apparatus according to claim 12 including means for deactivating saidconveying means in response to a defect sensing so as to position thesensed defect between said pair of cutting means.
 14. Apparatusaccording to claim 12 including lumber support means for supporting apiece of lumber in said path and movable away from a supported lumberpiece following activation of said pair of cutting means to divert thesupported piece laterally downwardly from said path under the influenceof gravity.
 15. Apparatus according to claim 14 including an inclinedsorting slideway means and an inclined transfer slideway means declinedin opposite directions below said lumber support means and divertermeans at the juncture of said slideways operable following a cuttingoperation for diverting lumber sections dropped from said path onto oneor the other of said slideway means.
 16. Apparatus according to claim 12including infeed means at an infeed end of said linear path upstream ofsaid cutting means including sensor means for sensing the presence of apiece of lumber at said infeed end and means engageable with said piecein response to a presence sensing of said sensor means for conveyingsaid piece endwise toward said defect-cutting means along said path. 17.Apparatus according to claim 12 including length-sensing meansdownstream of said cutting means for measuring a specified minimumlength of lumber extending downstream of said cutting means and meansfor diverting lengths greater than said specified minimum length fromsaid path to a second cutting station and for diverting lengths lessthAn said specified minimum length to a sorting means removed from saidsecond cutting station.
 18. Apparatus according to claim 17 includingsecond length-sensing means upstream of said cutting means for measuringa specified minimum length of lumber extending upstream of said cuttingmeans and means operable to divert upstream lengths less than saidspecified minimum upstream length from said path to said sorting meansremoved from said second cutting station and operable to convey upstreamlengths greater than said specified minimum upstream length along saidpath toward said cutting means for processing by said defect-sensing and-cutting means.
 19. An apparatus for cutting lumber to random orspecified clear lengths comprising: means for conveying lumber endwisealong a linear path, a pair of closely spaced-apart defect-cutting meanshaving parallel cutting planes extending across said path,defect-sensing means for sensing the presence of a defect between saidpair of cutting means, means for actuating said pair of cutting meanssimultaneously in response to a defect sensing to cut a defectivesection from said piece, means along said path for sensing a specifiedlong clear length in a given piece of lumber, and means including saidconveyor means operable in response to a specified long-length sensingfor positioning said piece with respect to one of said pair ofdefect-cutting means and for actuating said one defect-cutting means ina manner to cut said piece to the specified long clear length sensed.20. Apparatus according to claim 19 wherein said specified long clearlength-sensing means includes means for sensing the longest of multiplespecified long clear lengths and wherein said means operable in responseto said sensing includes means for positioning said piece with respectto said one cutting means in a manner so as to cut from said piece thelongest clear length sensed.
 21. Apparatus according to claim 19including means operable to divert random clear lengths less than saidspecified long clear length to a cut-to-length cutting station and fordiverting clear lengths cut to said specified long clear length to acollection point removed from said cut-to-length station.
 22. Apparatusaccording to claim 19 wherein said long clear length-sensing meansincludes a defect sensor along said linear path upstream of said pair ofcutting means and at least one end-of-piece sensor along said pathdownstream of said cutting means for sensing the leading end of a piece,with the distance between said upstream defect sensor and saiddownstream end-of-piece sensor determining said long specified clearlength, said long clear length-positioning means including a stop meanspositioned downstream of said end-of-piece sensor and spaced from saidone cutting means a distance corresponding to said specified long clearlength.
 23. Apparatus according to claim 22 including a plurality ofend-of-piece sensors spaced along said linear path downstream of saidpair of cutting means determining a plurality of specified long clearlengths and a plurality of extendible stops downstream of saidend-of-piece sensors, each stop corresponding to a different one of saidend-of-piece sensors, and means operable in response to a sensing of thelongest specified clear length to extend the corresponding one of saidstops into said path to determine the cutting position of a piecedownstream with respect to said one defect-cutting means to enablecutting the longest specified clear length sensed.
 24. An apparatus forcutting lumber to random or specified clear lengths comprising: meansfor conveying lumber endwise along a linear path, a pair of closelyspaced-apart defect-cutting means having parallel cutting planesextending across said path, defect-sensing means for sensing thepresence of a defect between said pair of cutting means, means foractuating said pair of cutting means simultaneously in response to adefect sensing To cut a defective section from said piece, firstmeasuring means for measuring a specified minimum cut length extendingdownstream from said pair of cutting means and means for divertingrandom lengths greater than said specified minimum length from saidlinear path to a cut-to-length cutting station and for diverting randomlengths less than said specified minimum length to a collecting stationbypassing said cut-to-length station, second measuring means formeasuring a minimum cut length extending upstream from said cuttingmeans and means for diverting upstream lengths less than said specifiedminimum upstream length from said path to a collection station bypassingsaid cut-to-length station and for reactivating said conveyor means toconvey upstream lengths greater than said minimum specified upstreamlength along said path toward said pair of cutting means, thirdmeasuring means for measuring a specified long clear length in a pieceof lumber extending from the leading end of said piece, and meansoperable in response to a measurement of said specified long clearlength in a piece for positioning said piece with respect to one of saidpair of cutting means so that the specified long clear length extendsdownstream from said one cutting means and for activating said onecutting means only to cut said specified long clear length from saidpiece.
 25. An apparatus for cutting lumber to specified lengthscomprising: length-cutting means defining a cutting plane, stop barmeans extending normal to said cutting plane and including a series ofprogrammable depressible stop and length-sensing means spaced atpredetermined distances from and on one side of said cutting planecorresponding to specified lengths of lumber to be cut, means fordelivering a random length of lumber to a position extending along saidstop bar means with one end of said piece adjacent said cutting plane,drive means for pressing said piece toward said stop bar means todepress one or more of said stop and sensing means and for driving saidpiece endwise in opposite directions along said stop bar means, andcontrol means operable in response to the presence of said piece alongsaid stop bar means first to operate said drive means in one directionto drive said random length toward said cutting plane until a depressedone of said stop and sensing means is released and then in response tosuch release to reverse said drive means to drive the opposite end ofsaid random length against said released stop means and then to actuatesaid cutting means to cut said random-length piece to the longestspecified length as sensed by said stop and sensing means, saidlength-cutting means being at a length-cutting station and including: adefect-cutting station above said length-cutting station, saiddefect-cutting station including defect-cutting means operable to cutdefective sections from a length of lumber to produce clear pieces ofrandom length, said defect-cutting means including a defect-cuttingplane determining one end of a clear piece and being in approximatevertical alignment with said length-cutting plane, said delivering meansincluding inclined slide means extending between said defect-cuttingstation and said length-cutting station, and movable lumber-supportmeans at said defect-cutting station movable from a support positionabove said slide means for supporting lumber at said defect-cuttingstation in parallel relation to the supported position of lumber at saidlength-cutting station, to a release position for dropping a clear piecefrom said defect-cutting station onto said slide means for sidewaysgravity delivery to said length-cutting station.
 26. An apparatus forcutting lumber to random or specified clear lengths comprising: meansfor conveying lumber endwise along a linear path, a defect-cutting meanshaving a cutting plane extending across said path, defect-sensing meansfor sensing the presence of a defect in a lumber piece traveling alongsaid path, means for actuating said cutting means in response to adefect sensing to cut a defective section from said piece, movablelumber-support means for supporting a piece of lumber in said path andupstream and downstream from said cutting means, and inclined slidewaymeans extending downwardly from and below said path along a planegenerally parallel to said path, said lumber-support means being movableaway from a supported piece in response to operation of said cuttingmeans to drop a supported piece onto said slideway means, said slidewaymeans includes an inclined transfer slideway extending downwardly in onedirection from said path and an inclined sorter slideway extendingdownwardly in an opposite direction from said path, and diverter meansat the juncture of said sorter and transfer slideways below said supportmeans and pivotable to positions to define extensions of said slidewaysfor directing pieces dropped from said path selectively onto one or theother of said slideways.
 27. Apparatus according to claim 26 includinglength-sensing means along said path upstream and downstream of saidcutting means and operable to position said diverter means so that (1)lumber portions extending upstream and downstream of said cutting meansof less than a specified length are diverted onto said sorter slidewayafter cutting and (2) lumber portions extending downstream of saidcutting means of greater than said specified length are diverted ontosaid transfer slideway.
 28. An apparatus for cutting lumber to random orspecified clear lengths comprising: means for conveying lumber endwisealong a linear path, a defect-cutting means having a cutting planeextending across said path, defect-sensing means for sensing thepresence of a defect in a lumber piece traveling along said path, meansfor actuating said cutting means in response to a defect sensing to cuta defective section from said piece, movable lumber-support means forsupporting a piece of lumber in said path and at said cutting means, andinclined slideway means extending downwardly from and below said pathalong a plane generally parallel to said path, said lumber-support meansbeing movable away from a supported piece following operation of saidcutting means to drop a supported piece onto said slideway means, saidslideway means including a transfer slideway extending downwardly in onedirection from said path and a sorter slideway extending downwardly inan opposite direction from said path, diverter means at the juncture ofsaid sorter and transfer slideways for directing pieces dropped fromsaid path selectively onto one or the other of said slideways,length-sensing means along said path upstream and downstream of saidcutting means and operable to position said diverter means so that (1)lumber portions extending upstream and downstream of said cutting meansof less than a specified length are diverted onto said sorter slidewayafter cutting and (2) lumber portions extending downstream of saidcutting means of greater than said specified length are diverted ontosaid transfer slideway, selectively applied lumber stop means along saidpath at a predetermined distance from one of said pair of cutting means,and a defect sensor upstream of one of a closely spaced pair of saidcutting means and a lumber sensor downstream of said cutting means at adistance from said upstream defect sensor corresponding to saidpredetermined distance, said defect and lumber sensors being operable toapply said lumber stop means when said lumber sensor senses a lumberpiece before said upstream defect sensor senses a defect in said piece,and means operable to actuate only said one cutting means of said pairwhen said piece abuts said stop means, to cut said piece to a specifiedclear length.
 29. Apparatus according to claim 28 including meansoperable to position said diverter meanS to divert said piece ofspecified clear length onto said sorter slideway after operation of saidone cutter means.